The Roman poet Virgil called it the principal river of Tartarus, from which the Styx and Cocytus both sprang.[5] The newly dead would be ferried across the Acheron by Charon in order to enter the Underworld.[6]

The Suda describes the river as "a place of healing, not a place of punishment, cleansing and purging the sins of humans".[8]

According to later traditions, Acheron had been a son of Helios and either Gaia or Demeter, who had been turned into the Underworld river bearing his name after he refreshed the Titans with drink during their contest with Zeus.[9] By this myth, Acheron is also the father of Ascalaphus by either Orphne[10] or Gorgyra.[11]

The river called Acheron with the nearby ruins of the Necromanteion is found near Parga on the mainland opposite Corfu. Another branch of Acheron was believed to surface at the Acherusian cape (now Karadeniz Ereğli in Turkey) and was seen by the Argonauts according to Apollonius of Rhodes. Greeks who settled in Italy identified the Acherusian lake into which Acheron flowed with Lake Avernus. Plato in his Phaedo identified Acheron as the second greatest river in the world, excelled only by Oceanus.

Following Greek mythology, Charon ferries souls across the Acheron to Hell. Those who were neutral in life sit on the banks

He claimed that Acheron flowed in the opposite direction from Oceanus beneath the earth under desert places.
The word is also occasionally used as a synecdoche for Hades itself. Virgil mentions Acheron with the other infernal rivers in his description of the underworld in Book VI of the Aeneid. In Book VII, line 312[12] he gives to Juno the famous saying, flectere si nequeo superos, Acheronta movebo: 'If I cannot bend the will of Heaven, I shall move Hell.' The same words were used by Sigmund Freud as the dedicatory motto for his seminal book The Interpretation of Dreams, figuring Acheron as psychological underworld beneath the conscious mind.

The name Acheron was used as a reference within the Alien film series for the planet LV426 (where the crashed alien vessel containing the face-huggers was originally found). Known solely by its alphanumeric designation during the first film, the planet was named as Acheron during the sequel Aliens.